24 Different Parts of CNC Machine and Their Functions

Hello, friends in this article you will know 24 different parts of CNC machines and their functions along with this we will also know their applications, advantages, disadvantages, and many more.

Many objects such as airplanes, robots, space rockets, cars, and boats are made with the help of a manufacturing technique called CNC machining which is done by CNC machine.

CNC machines are preferred by engineers worldwide because they are one of the most precise manufacturing techniques.

If you're an engineer, you are probably quite familiar with CNC machines.

CNC machining is a subtractive manufacturing technique because parts are manufactured by removing material from a solid block or called a blank or workpiece. 

Almost any type of hard material can be machined through CNC. Some of the most common materials are aluminum, brass, ABS, Delrin, and nylon.

So, without wasting time let's get started.

What is CNC Machine?

Computer Numerical Control (CNC) is one in which the functions and motions of a machine tool are controlled by means of a prepared program containing coded alphanumeric data. 

CNC can control the motions of the workpiece or tool, the input parameters such as feed, depth of cut, speed, and the functions such as turning the spindle on/off, turning coolant on/off, etc.

Parts of CNC Machines and Their Functions

The following parts are used in CNC machines:
  • Control Panel
  • Input Devices
  • Part Program
  • Machine Control Unit
  • Machine Tools
  • Driving System
  • Feedback System
  • PLC Panel
  • Display Unit
  • Servo Motor
  • Tool Turret
  • Tailstock
  • Spindle
  • Guide Ways
  • Chuck
  • Axis Motor
  • Ball Screw
  • Chip Guard Door
  • Hydraulic Oil Tank
  • Lubrication Oil Tank
  • Coolant Tank 
  • Machine Bed
  • Carriage
  • Stabilizer

Show in the figure the parts of the CNC machine are described below in detail.

parts of CNC machine
Parts of CNC Machine

Control Panel

The control panel of the CNC machine is also called the operating panel because the CNC machine is controlled by this control panel.

Input Devices

These are the devices that are used to input the part program in the CNC machine. 

There are three commonly used input devices and these are punch tape reader, magnetic tape reader, and computer via RS-232-C communication.

Part Program

A part program is a series of coded instructions, required to produce a part. 

It controls the movement of the machine tool and on or off control of auxiliary functions such as spindle rotation and coolant. The coded instructions are composed of letters, numbers, and symbols.

The part program is a detailed set of commands to be followed by the machine tool.

Each command specifies a position in the Cartesian coordinate system (x,y,z) or motion such as workpiece travel or cutting tool travel, machining parameters, and on/off function.

Part programmers should be well versed with machine tools, machining processes, effects of process variables, and limitations of CNC controls.

Machine Control Unit

The machine control unit (MCU) is the heart of a CNC system. 

The machine control unit consists of the data processing unit (DPU) and the control loop unit (CLU).

The DPU decodes the information contained in the part program, processes it, and provides instructions to the CLU.

The CLU operates the drives attached to the machine lead screw and feedback signals on the actual position and velocity of each one of the axes. The drive units are actuated by voltage pulses.

It is used to perform the following functions:
  1. To read the coded instructions.
  2. To decode the coded instructions.
  3. To implement interpolations (linear, circular, and helical) to generate axis motion commands.
  4. To feed the axis motion commands to the amplifier circuits for driving the axis mechanisms.
  5. To receive the feedback signals of position and speed for each drive axis.
  6. To implement auxiliary control functions such as coolant or spindle on/off and tool change.

Machine Tools

The machine tools perform useful work.

A machine tool consists of a worktable, one or more spindles, motors and controls, cutting tools, work fixtures, etc.

Driving System

The requirement is that the driving system has to respond accurately according to the programmed instructions.

A drive system consists of amplifier circuits, drive motors, and ball lead screws. 

The MCU feeds the control signals like the position and speed of each axis to the amplifier circuits. 

The control signals are augmented to actuate drive motors which in turn rotate the ball lead screws to position the machine table.

The motor is coupled either directly or through a gearbox to the machine lead screw to move the machine slide or the spindle.

Three types of electrical motors are commonly used:
  1. DC Servo motor
  2. AC Servo motor
  3. Stepping motor

Feedback System

This system consists of transducers that act like sensors. It is also called a measuring system. 

It contains position and speed transducers that continuously monitor the position and speed of the cutting tool located at any instant.

PLC Panel

The CNC machine is controlled by the PLC panel. 

PLC stands for Programmable Logic Control. 

PLC is also called the brain of a CNC machine.

Display Unit

The interface between the machine and the operator.

The Display Unit displays:
  1. Position of the machine slide
  2. Spindle RPM
  3. Feed rate
  4. Part programs
  5. Graphics simulation of the tool path.

Servo Motor

The CNC machine is fitted with a servo motor to rotate the spindle. The servo motor automatically controls the RPM and rotates the spindle clockwise, and anti-clockwise according to requirement.

Tool Turret

The tool turret is also called ATC which means automatic tool changer, it automatically changes the tool according to the operation.

The tool turret has a tool magazine with different cutting tools.

Tail Stock

The main function of tail stock is to support long and heavy jobs. 

The tail stock has a revolving center, also known as a foot stock and dead center.


The spindle is a type of hollow shaft with a chuck attached to it. The spindle acts to rotate the chuck.

It is the heart of a machine tool and consists of a spindle assembly and a spindle drive system.


Guideways control the direction of the table on which a tool or work is held.

It absorbs all static and dynamic forces.


The main function of the chuck in the CNC machine is to clamp the component. 

Mostly hydraulic chuck is used in CNC machines as hydraulic chuck clamps the job firmly. 

CNC machines use different design chucks according to the component.

Axis Motor

The CNC machine has an axis motor to control the axis. 

The Axis motor converts circular motion to linear motion. It is due to the axis motor that the x-axis and z-axis of the CNC machine travel.

Ball Screw

Ball Screw Converts rotary motion to linear motion works on the principle of rolling friction profile threads machine on the shaft and balls meshed inside the nut.

Chip Guard Door

The CNC machine is equipped with a chip guard door, this machine acts as a safety for the operator. 

When the CNC machine works on metal, small metal chips come out of the machine and coolant runs in the machine, so the metal chips and coolant do not come out of the machine, so the CNC door is closed. 

This protects the safety of the machine operator.

Hydraulic Oil Tank

The hydraulic tank of the CNC machine consists of hydraulic oil, which consists of a motor that clamps and decamps the chuck by creating hydraulic oil pressure.

Lubrication Oil Tank

The CNC machine has a lubrication oil tank to deliver lubrication oil to the continuously working parts of the CNC machine.

Coolant Tank

The CNC machine has a coolant tank in which the coolant is filled. 

The coolant is used in the CNC machine to cool the job, cutting tools. 

When the cutting tool works on metal, both the tool and the component are heated. Using a continuous coolant in the CNC machine increases the tool life of the cutting tool.

Machine Bed

A machine bed is the main body of the CNC machine. 

All the main components are bolted on it such as spindle stock, tailstock, axis assembly, guidelines, tool turret, etc.

It limits heat distortion and provides mechanical stability.


It is located between the headstock and the tailstock.  

It is used to hold and move the tool post along the bed either towards or away from the headstock. 

It slides on the guideways.


The CNC machine has a stabilizer to control the electricity.

How does CNC Machine Work?

See in the figure the working process of the CNC machine which is described in detail below.

working process of CNC machine

  1. First, the part programming is fed into the CNC's MCU.
  2. The MCU processes all the data and according to the program prepared, it generates all the motion commands and sends them to the driving system.
  3. The motion system works as a motion command sent by the MCU. The drive system controls the speed and velocity of the machine tool.
  4. The feedback system records the position and velocity measurement of the machine tool and sends a feedback signal to the MCU.  
  5. In the MCU, the feedback signals are compared with the reference signals and if there are errors, it corrects them and sends new signals to the machine tool to be corrected.
  6. A display unit is used to view all commands, programs, and other important data. It acts as the eye of the machine.

Application of CNC Machine

Almost every manufacturing industry uses CNC machines. 

With an increase in the competitive environment and demands, the demand for CNC usage has increased to a greater extent. The machine tools that come with the CNC are lathes, mills, shapers, welding, etc. 

The industries that are using CNC machines are the automotive industry, metal-removing industries, industries of fabricating metals, electrical discharge machining industries, wood industries, etc.

Advantages of CNC Machine

CNC machine has the following advantages:
  1. It can produce jobs with the highest accuracy and precision than any other manual machine.
  2. It can be run 24 hours a day.
  3. A highly skilled operator is not required to operate a CNC machine.
  4. Operators can easily make changes and improvements and reduce the delay time.
  5. It has the capability to produce complex designs with high accuracy in the minimum possible time.
  6. Modern design software such as CAD, and CAM allows the designer to simulate the manufacturer of his/her idea.
  7. Fewer workers are required to operate a CNC machine and save labor costs.

Disadvantages of CNC Machine

CNC machine has the following disadvantages:
  1. The cost of a CNC machine is very high compared with a manually operated machine.
  2. The parts of the CNC machines are expensive.
  3. The maintenance cost in the case of a CNC machine is quite high.
  4. It does not eliminate the need for costly tools.

So here you have to know the different parts of CNC machines and their functions. 

If you have any doubts then you are free to ask me by mail or on the contact us page.

Thank You.

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